Mellow SB2040 issue with on-board extruder driver

[Hot Toddy]

Hi, 

Noob to the forum. I have already searched threads on the Mellow Fly SB2040 canbus board but not found anything relating to my particular issue. Hoping someone can help.

I've just built a Voron Trident  with an Octopus v1.1 main board, and went the canbus route with the Mellow SB2040. I have CanBoot and Kilpper installed and working successfully with a canbus speed set to 1,000,000. To not complicate matters, I chose to use the native Octopus tmc2209 driver to run the extruder while I got all the other steppers configured  and working, along with the hotend heater, temp sensors and Klicky probe over canbus to the SB2040. All that is now working fine. I can home, tram the bed, heat the hotend and run PID calibration against the temp sensors.

I've now attempted to switch to controlling the extruder over canbus (using the native tmc2209 driver on the SB2040) and run into a rather strange issue. The control of the extruder over canbus works successfully, and runs the extruder in the right direction, but will only do so for one command. Thereafter, I have the reboot the firmware to control the extruder again. So I was able to successfully calibrate the extruder with a G1 E100 F100 command to push 100mm of fliament through it. But if I try running the command again I get nothing! Which leaves me at a bit of a loss, as I had concluded the canbus communication was configured correctly and working well.

I've loaded the 'can-utils' package on the Raspberry Pi and tried running 'canbusload' and 'candump' commands (as suggested at https://github.com/akhamar/voron_canbus_octopus_sb2040)  but I really don't know what I'm looking at. Any suggestions as to what's going on with my setup, or what I can do to test/debug it, would be gratefully received.

Thanks